Management and treatment options when facing malignant ureteral obstruction

High early mortality following percutaneous nephrostomy in metastatic cancer: a national analysis of outcomes

OBJECTIVES

To assess the outcomes of percutaneous nephrostomy in England for renal decompression, in the context of metastatic cancer.

METHODS

Retrospective observational study of all patients undergoing nephrostomy with a diagnosis of metastatic cancer from 2010 to 2019 in England, identified and followed up within Hospital Episode Statistics.The primary outcome measure was mortality (14-day and 30-day postprocedure). Secondary outcomes included subsequent chemotherapy or surgery and direct complications of nephrostomy.

RESULTS

10 932 patients were identified: 58.0% were male, 51.0% were >70 years old and 57.7% had no relevant comorbidities (according to Charlson's criteria, other than cancer).1 in 15 patients died within 14 days of nephrostomy and 1 in 6 died within 30 days. Factors associated with higher 30-day mortality were the presence of comorbidities (Charlson score 1-4 (OR 1.27, 95% CI 1.08 to 1.50, p=0.003), score 5+ (OR 1.29, 95% CI 1.14 to 1.45), p<0.001)); inpatient nephrostomy (OR 3.76, 95% CI 2.75 to 5.14, p<0.001) and admitted under the care of specialities of internal medicine (OR 2.10, 95% CI 1.84 to 2.40, p<0.001), oncology (OR 1.80, 95% CI 1.51 to 2.15, p<0.001), gynaecology/gynaeoncology (OR 1.66, 95% CI 1.21 to 2.28, p=0.002) or general surgery (OR 1.62, 95% CI 1.32 to 1.98, p<0.001)), compared with urology.25.4% received subsequent chemotherapy. Receiving chemotherapy was associated with younger patients (eg, age 18-29 (OR 4.04, 95% CI 2.66 to 6.12, p<0.001) and age 30-39 (OR 3.07, 95% CI 2.37 to 3.97, p<0.001)) and under the care of oncology (OR 1.60, 95% CI 1.40 to 1.83, p<0.001) or gynaecology/gynaeoncology (OR 1.64, 95%CI 1.28 to 2.10, p<0.001) compared with urology.43.8% had subsequent abdominopelvic surgery. Not receiving surgery was associated with inpatient nephrostomy (OR 0.82, 95%CI 0.72 to 0.95,p=0.007): non-genitourinary cancers (eg, gynaecology/gynaeoncology cancer (OR 0.86, 95% CI 0.74 to 0.99, p=0.037)); and under the care of a non-surgical specialty (medicine (OR 0.69, 95% CI 0.63 to 0.77, p<0.001), oncology (OR 0.58, 95% CI 0.51 to 0.66, p<0.001)).24.5% of patients had at least one direct complication of nephrostomy: 12.5% required early exchange of nephrostomy, 8.1% had bleeding and 6.7% had pyelonephritis.

CONCLUSIONS

The decision to undertake nephrostomy in patients with poor prognosis cancer is complex and should be undertaken in a multidisciplinary team setting. Complication rates are high and minimal survival benefit is derived in many patients, especially in the context of emergency inpatient care.

Cost-effectiveness of Resonance® metallic ureteral stent compared with standard polyurethane ureteral stents in malignant ureteric obstruction: A cost-utility analysis

Background

Malignant ureteral obstruction (MUO) is a frequent challenge for urologists. Patients have poor prognoses, treatment aims to improve quality-of-life while optimising renal function. Standard practice in the United Kingdom is to use polyurethane stents, which require frequent surgical replacements for blockages and encrustation. More durable metallic stents are available, although these incur an increased initial purchase price.

Aims

We aim to assess whether the use of polyurethane double-J (JJ) or metallic stent, Resonance® is more cost-effective for managing MUO in the UK healthcare setting.

Methods

A Markov model was parameterised to 5 years with costs and health-related quality-of-life consequences for treating MUO with Resonance metallic stent (Cook Medical), versus standard JJ stents, from the UK care system perspective, with 3.5% discounting. Deterministic and probabilistic sensitivity analyses were undertaken to assess the effect of uncertainty.

Results

Over 5 years, approximately four fewer repeat surgical interventions were estimated in the metallic stent arm compared with the JJ stent, driving a 23.4% reduction in costs. The mean estimates of costs and benefits indicate that treatment of MUO with Resonance for 5 years is dominant over JJ stents. Over 5 years a cost-saving of £2164.74 and a health gain of +0.046 quality-adjusted life years (QALYs) per patient is estimated. With a maximum willingness to pay of £20 k per QALY, a net monetary benefit (NMB) of £3077.83 is estimated. Probabilistic sensitivity analysis at a willingness to pay threshold of £20 000 indicates an 89.3% probability of Resonance being cost-effective over JJ stents. Within 1-year savings of £726.53 are estimated driven by a reduction of two fewer repeat surgical interventions when using the metallic stent.

Conclusions

Resonance metallic stents for the treatment of MUO reduce the number of repeat procedures and could be a cost-effective option for the treatment, potentially offering efficiencies to the healthcare system.

Malignant ureteral obstruction: comparison of metallic, 8 French and 6 French ureteric stents after failure of initial ureteric stent

PURPOSE

Malignant ureteric obstruction is a significant management challenge. The failure of ureteric stents often leads to long-term nephrostomy tubes. This is delayed for as long as possible due to its' associated morbidity. Several types of ureteric stents are available, however there is little evidence demonstrating which stents are better for preventing progression to nephrostomy tubes. This study looked to determine whether a new 6 French (Fr) polymer stent, 8Fr polymer stent or metallic stent achieved a longer functional duration once the initial polymer ureteric stent failed.

METHODS

A retrospective, longitudinal study was performed at a single tertiary institution. All patients who underwent ureteric stenting with a 6Fr polymer stent for malignancy between 2010 and 2020 were included. Patients were followed up until death with ureteric stent in situ or permanent nephrostomy tube insertion.

RESULTS

A total of 46 patients (66 ureters) had ureteric stents inserted for malignancy. From initial ureteric stent failure, 10 stents were changed to a new 6Fr polymer stent, 42 were changed to an 8Fr polymer stent and 14 were changed to a Resonance® 6Fr metallic stent. The Resonance 6Fr metallic stent had the longest median functional duration of 14 months (p = 0.012).

CONCLUSION

Resonance® 6Fr metallic stents appear to have a significantly longer functional duration than a new 6Fr polymer stent or 8Fr polymer stent, which may allow patients to enjoy a better quality of life and delay permanent nephrostomy tube insertion.

[Pathology of the kidneys in malignant tumors of various localizations and antitumor therapy]

Non-tumorlesions of the kidneys in malignant neoplasms are very diverse. They can alter the results of chemotherapy and lead to death in the long term. In this regard, the related discipline of onconephrology has increasingly begun to be identified, which emphasizes the importance of diagnosing non-tumor kidney lesions in this category of patients. This review is devoted to the classification, diagnosis, course, prevention and treatment of non-tumor kidney lesions in patients with malignant neoplasms. There are four groups of lesions: mechanical damage; nephropathy due to anticancer therapy; paraneoplastic nephropathy; lesions associated with metabolic disorders. Kidney lesions in patients with malignant neoplasms are characterized by a variable course. In some cases, acute renal failure develops. Others are characterized by an asymptomatic course with an outcome in nephrosclerosis. Timely diagnosis and treatment of kidney lesions in malignant neoplasms can improve the quality of life and prognosis of patients with malignant neoplasms.

Impact of long-term indwelling JJ stent on renal volume and renal function

BACKGROUND

Data is lacking about long-term impact of JJ stents (JJst) on renal parenchyma. The aim of the study was to assess the evolution of renal parenchyma in patients with JJst indwelling for more than two years, and to find predictive factors for the development of renal atrophy.

METHODS

Consecutive patients with JJst indwelled for more than 24 months, with a history of cancer, were retrospectively included. Replacements of JJst were scheduled every six months, or earlier in case of premature obstruction. Patient characteristics at the time of insertion of JJst, history of indwelling JJst and most recent data (serum creatinine, cancer status, definite JJst removal, renal volume (RV) with3D software) were recorded.

RESULTS

With a median follow-up of 4 years, 73 patients were included. The indication of JJst insertion was mostly external compression (65.8%). CT scans were available to assess RV evolution in 66 patients (90.4%). Median shrinkage of RV was higher when JJ stenting was unilateral versus bilateral: -40% (-63; -15) versus -16% (-36; -3), P<0.001. The duration of indwelling JJst was the only statistically significative predictive factor of renal shrinkage in multivariate analysis (OR [CI 95%]: 1.35 [1.10-1.66] P=0.004). Median relative change from baseline in eGFR was -22% (-45%; -5%.). No statistically significant predictive factors of eGFR evolution were found in univariate and multivariate analysis.

CONCLUSIONS

Unilateral JJst for more than 2 years was associated with a significant shrinkage of renal parenchyma, especially since the duration of the indwelling stent was long.

Unveiling the Challenges in Tandem Ureteral Stent Management for Malignant Ureteral Obstruction: Failure Rate, Risk Factors, and Durability of Their Replacement

BACKGROUND

Malignant ureteral obstruction (MUO) is a sequela of advanced malignant disease that requires renal drainage, with tandem ureteral stents (TUSs) being a viable option. This study aimed to evaluate the TUS failure rate, associated risk factors, and the feasibility of replacing failed TUSs with a new pair of stents.

METHODS

A retrospective analysis of MUO patients treated with TUS insertion from 2014 to 2022 was conducted. TUS failure was defined as urosepsis, recurrent urinary tract infections, acute kidney failure, or new hydronephrosis on imaging. Cox proportional hazard regression analysis identified the independent predictors of TUS failure.

RESULTS

A total of 240 procedures were performed on 186 patients, with TUS drainage failing in 67 patients (36%). The median time to failure was 7 months. Multivariate analysis revealed female gender (OR = 3.46, p = 0.002), pelvic mass (OR = 1.75, p = 0.001), and distal ureteral obstruction (OR = 2.27, p = 0.04) as significant risk factors for TUS failure. Of the failure group, 42 patients (22.6%) underwent TUS replacement for a new pair. Yet, 24 (57.2%) experienced a second failure, with a median time of 4.5 months. The risk factors for TUS second failure included a stricture longer than 30 mm (OR = 11.8, p = 0.04), replacement with TUSs of the same diameter (OR = 43, p = 0.003), and initial TUS failure within 6 months (OR = 19.2, p = 0.006).

CONCLUSIONS

TUS insertion for the treatment of MUO is feasible and has good outcomes with a relatively low failure rate. Primary pelvic mass and distal ureteral obstruction pose higher risks for TUS failure. Replacing failed TUSs with a new pair has a success rate of 42.8%. Consideration should be given to placing larger diameter stents when replacing failed TUS.

Effect of ureteral stent length and implantation position on migration after implantation

BACKGROUND

Ureteral obstruction is a urinary system disease that causes urinary retention, renal injury, renal colic, and infection. Ureteral stents are often used for conservative treatment in clinics, and their migration usually results in ureteral stent failure. The migrations include proximal migration to the kidney side and distal migration to the bladder side, but the biomechanism of stent migration is still unknown.

METHOD

Finite element models of stents with lengths from 6-30 cm were developed. The stents were implanted into the middle of the ureter to analyze the effect of stent length on its migration, and the effect of stent implantation position on 6-cm-long stent migration was also observed. The stents' maximum axial displacement was used to assess the ease of stent migration. A time-varying pressure was applied to the ureter outer wall to simulate peristalsis. The stent and ureter adopted friction contact conditions. The two ends of the ureter were fixed. The radial displacement of the ureter was used to evaluate the effect of the stent on peristalsis.

RESULTS AND DISCUSSION

The maximum migration occurs in the positive direction for a 6-cm-long stent implanted at the proximal ureter (CD and DE), but in the negative direction at the distal ureter (FG and GH). The 6-cm-long stent demonstrated almost no effect on ureteral peristalsis. The 12-cm-long stent diminished the radial displacement of the ureter from 3-5 s. The 18-cm stent diminished the radial displacement of the ureter from 0-8 s, and the radial displacement within 2-6 s was weaker than other time. The 24-cm stent diminished the radial displacement of the ureter from 0-8 s, and the radial displacement within 1-7 s was weaker than other time.

CONCLUSION

The biomechanism of stent migration and ureteral peristalsis weakening after stent implantation was explored. Shorter stents were more likely to migrate. The implantation position had less influence on ureteral peristalsis compared with the stent length, which provided a reference for stent design aimed at reducing stent migration. Stent length was the main factor affecting ureteral peristalsis. This study provides a reference for the study of ureteral peristalsis.

Electromechanically Functionalized Ureteral Stents for Wireless Obstruction Monitoring

While millions of ureteral stents are placed in patients with urinary tract issues around the world every year, hydronephrosis still poses great danger to these patients as a common complication. In the present work, an intelligent double-J ureteral stent equipped with a micro pressure sensor and antenna circuitry is investigated and prototyped toward enabling continuous wireless monitoring of kidney pressure to detect a ureteral obstruction and the resultant hydronephrosis via the indwelling stent. This electromechanically functionalized "intelligent" ureteral stent acts as a radiofrequency resonator with a pressure-sensitive resonant frequency that can be interrogated using an external antenna to track the local pressure. The prototype passes mechanical bending tests of up to 15 cm radius of curvature and shows wireless sensing with a sensitivity of 3.1 kHz/mmHg in artificial urine, which represents 25× enhancement over the preceding design, using an in vitro model with test tissue layers and a pressure range that functions within the conditions found in hydronephrotic conditions. These promising results are expected to propel intelligent ureteral stent technology into further clinical research.

External validation of a simplified prognostic model for survival in patients with extrinsic malignant ureteral obstruction treated with tandem ureteral stents - a retrospective cohort study

INTRODUCTION

Prognostic models of survival can identify patients with extrinsic malignant ureteral obstruction who will benefit from long-term drainage as offered by tandem ureteral stents. The study aims to validate a simplified prognostic model published by Cordeiro et al. and to identify additional prognostic predictors in a cohort of patients drained solely with tandem ureteral stents.

METHODS

Medical records of consecutive patients who underwent drainage of malignant ureteral obstruction with tandem ureteral stents between 2007 and 2020 were reviewed retrospectively; patients with benign ureteral obstruction were excluded. Risk factors for survival included were: [1] the number of malignancy-related events (categorized as ≥4 and <4) and [2] the Eastern Cooperative Oncology Group Index (categorized as ≥2 and <2)]. Patients with ≥1 risk factor were grouped as intermediate-unfavorable risk and those without risk factors as favorable risk. The Kaplan-Meier and log-rank tests were used for survival analysis. Univariable and multivariable Cox regression analyses were used to identify predictors of outcome.

RESULTS

The study cohort consisted of 65 patients; the median age was 60 years (IQR 51-72). The median follow-up time from diagnosis of hydronephrosis was 51 months (IQR 38-64). Estimated probabilities of survival at 1 month, 6 months 1 year, and 2 years were 100%, 87%, 75% and 57%, respectively in the favorable risk group (n = 40), and in the intermediate-unfavorable risk group (n = 25), 96%, 72%, 52%, and 20%, respectively, (p = .003). On multivariable analysis, the presence of ≥4 malignancy-related events (HR = 2.04, 95% CI [1.07-3.86], p = .03) and lung metastasis (HR = 2.37, 95% CI [1.0-5.6], p = .05) were associated with shorter survival.

CONCLUSIONS

Our findings validate the prognostic model published by Cordeiro et al. The model can be applied when counseling patients being considered for drainage with tandem ureteral stents.

Top Ten Tips Palliative Care Clinicians Should Know About Urological Care

Patients receiving palliative care (PC) can present with or develop a host of urological needs or complications. These needs can include attention to sexual health, urinary incontinence, genitourinary bleeding, and urinary tract obstruction by benign, malignant, or urinary stone diseases. These varied conditions require that PC clinicians understand invasive and noninvasive medical, surgical, and radiation options for treatment. This article, written by a team of urologists, geriatricians, and PC specialists, offers information and guidance to PC teams in an accessible "Top Ten Tips" format to increase comfort with and skills around assessment, evaluation, and specialist referral for urological conditions common in the PC setting.

Clinical phenotypes and long-term outcome of kidney involvement in Erdheim-Chester histiocytosis

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis that frequently infiltrates the peri-kidney space ("hairy kidney" appearance), kidney pelvis and proximal ureters, leading to obstructive uropathy. Here, we analyzed the clinical characteristics, imaging findings and long-term kidney outcome of a large multicenter cohort comprising 195 consecutive patients with ECD. Retroperitoneal peri-kidney or peri-ureteral involvement was detected at diagnosis in 147 patients. Of them, 70 had hydronephrosis (bilateral in 47), and 16 with kidney atrophy (unilateral in 14). Kidney vascular peduncle infiltration was found in 60 patients, and kidney artery stenosis in 31. The estimated glomerular filtration rate (eGFR) at diagnosis was significantly lower in patients with than in those without peri-kidney involvement (median 74 vs. 98 mL/min/1.73 m²). Ureteral stenting often failed to achieve kidney function recovery. A total of 181 patients received medical therapies: first-line treatments included interferon-α (61%), BRAF-inhibitors (17%), mTOR-inhibitors (7%), or other drugs (15%). These therapies were efficacious for ECD but rarely induced kidney function improvement (one-year eGFR increase over 25% in under 10% of patients). After a median of 43 months, 19% of patients died and 5% developed kidney failure. Among patients with peri-kidney involvement, 44% developed chronic kidney disease (CKD) 3-5 at five years vs. 5% of those without. Unadjusted predictors of advanced CKD and kidney failure/death were age over 50 years, hypertension, BRAFV600E mutation, and baseline eGFR. At multivariable analysis, cardiovascular comorbidities were associated with advanced CKD, and age over 50 years with kidney failure/death. Thus, kidney involvement is common in ECD and can lead to CKD or kidney failure despite effective medical therapies or urological procedures.

Which is the best way for patients with ureteral obstruction? Percutaneous nephrostomy versus double J stenting

BACKGROUND

Percutaneous nephrostomy (PCN) and Double J stenting (DJS) are the 2 main treatment options of ureteral obstruction. We evaluate which of these 2 methods is superior concerning the course of procedure, postoperative complication and quality of life.

METHODS

A detailed review of electronic databases including PubMed, Embase, Cochrane Library, China Biology Medicine disc, China National Knowledge Infrastructure up to February 21st, 2021 was searched. Continuous data were evaluated using mean difference (MD) with 95% confidence interval (CI), while nominal data were analyzed by risk ratio (RR) with 95% CI. Meanwhile, we performed the subgroup analysis based on study design, disease type, sample size, sepsis, DJ diameter, nephrostomy diameter, anesthesia type and guidance under X-ray or ultrasound.

RESULTS

There were 18 previous studies included in current study. As a result, we found that there were significant differences in fluoroscopy time (MD = 0.31; 95% CI, 0.14-0.48, P < .001) and hospital stay (MD = 1.23; 95% CI, 0.60-1.85, P < .001). However, no statistic difference was detected in operative time (MD = 5.40; 95% CI, -1.78 to 12.58, P = .140) between the paired groups. Although DJS showed a higher rate of postoperative complications (25.19% vs 17.61%), there was no significant difference in the incidence of complications following DJS and PCN (RR = 0.92; 95% CI, 0.60-1.43; P = .720). Based on the EuroQol analysis, the 2 main treatment options had different impacts on quality of life. The pooled results showed that PCN patients reported more difficulties in self-care compared to DJS patients (RR = 3.07; 95% CI, 1.32-7.14; P = .009).

CONCLUSIONS

DJS is a safe and better method of temporary urinary diversion than PCN for management of ureteral obstruction with shorter fluoroscopy time and hospital stay. As for quality of life, patients receiving PCN had a distinct difficulty in self-care compared to those receiving DJS. However, these 2 treatment options often depends on the individual situation.

Comparison between antegrade versus retrograde ureteral stent placement for malignant ureter obstruction

PURPOSE

To compare the technical success of antegrade (AUS) and retrograde ureteral stent placement (RUS) in patients with malignant ureteral obstruction (MUO) and to determine the predictors of technical failure of RUS.

MATERIALS AND METHODS

This study retrospectively included 61 AUS (44 patients) performed under fluoroscopic guidance and 76 RUS (55 patients) under cystoscopic guidance performed in patients with MUO from January 2019 to December 2020. Technical success rates of the two techniques were compared using an inverse probability of treatment weighting (IPTW) analysis. Logistic regression was used to identify predictive factors for technical failures.

RESULTS

Technical success was achieved in 98.4% of the AUS group and 47.4% of the RUS group. After stabilized IPTW, the technical success rate was higher in the AUS group than in the RUS group (adjusted risk difference, 49.4% [95% CI, 35.4%-63.1%]). Independent predictors for technical failure of the RUS procedure were age ≥ 65 years (OR 5.56, 95% CI 1.73-21.27), ureteral orifice invasion (OR 4.21, 95% CI 1.46-13.46) and extrinsic cancer (OR 15.58, 95% CI 2.92-111.81).

CONCLUSIONS

The technical success rate of AUS was higher than that of RUS in patients with MUO. RUS failure was associated with age ≥ 65 years, cancer with ureteral orifice invasion, and extrinsic ureteral obstruction.

Management and outcomes of hydronephrosis in patients with metastatic extramammary Paget's disease: A retrospective analysis

Hydronephrosis in extramammary Paget's disease (EMPD) with distant metastasis (metastatic EMPD) has been observed in medical practice; however, its prognosis remains unclear. Retrospective analyses were performed to assess the management and outcomes of hydronephrosis in metastatic EMPD. During a follow-up of 44 patients with metastatic EMPD, 13 (30%) developed hydronephrosis. Ten (77%) of the 13 patients with hydronephrosis had impaired renal function (estimated glomerular filtration rate: <60 ml/min/1.73 m² ), and ureteral stents were placed in every patient with impaired renal function. The stent was placed successfully in all 10 patients, and their renal function recovered within a median period of 7 days. Importantly, each of these patients continued chemotherapy, and none of them experienced stent failure. The median overall survival time (OS) in patients with metastatic EMPD and hydronephrosis (n = 13) was 7.8 months. Treatment for hydronephrosis was not a significant factor for OS, and median OS in patients who underwent ureteral stent replacement (n = 10) was 14.7 months. Collectively, our results indicate that hydronephrosis is relatively common, and ureteral stent placement should be considered in cases of metastatic EMPD with hydronephrosis to maintain renal function and continue chemotherapy toward a better prognosis.

Cystoscopic surveillance protocol for ureteral stents used to manage malignant ureteral obstruction: reducing morbidity of frequent stent changes

PURPOSE

To evaluate a cystoscopic surveillance protocol used to mitigate morbidity associated with chronic ureteral stents for malignant ureteral obstruction (MUO).

MATERIALS AND METHODS

A retrospective cohort study was conducted at a tertiary, referral centre of consecutive MUO patients who were initially managed with a ureteral stent and subsequently followed using a cystoscopic 'MUO stent surveillance protocol'. Multivariable regression models evaluated factors associated with the following outcomes: number of stent changes, time to first stent change, and overall survival.

RESULTS

A total of 120 patients from May 2009 to December 2019 were included; mean age was 63 years, majority (76.7%) were female, and median follow-up for stented patients was 184 days. Majority (72%) of patients did not require a stent change at 3-months follow-up. Only 32% (19/60) required a stent change at their 6-month stent surveillance cystoscopy. Median time to first stent change was 158 days. Of 344 total number of stent surveillance cystoscopies performed, 39.5% (136/344) involved a stent change. Patients with a history of pelvic radiation (subdistribution hazard rate [sHR] 2.12, 95% CI 1.23 to 3.67, p=0.007) and with a history of bowel resection (sHR 2.06, 95% CI 1.05 to 4.03, p=0.036) were independently associated with earlier stent changes. No patients in the MUO stent surveillance protocol required ancillary procedures to deal with encrusted stents.

CONCLUSIONS

A cystoscopic 'MUO stent surveillance protocol' can reduce the morbidity and health care expenditures associated with stent changes among MUO patients, with median time to first stent change being 158 days and only 40% of surveillance cystoscopies involving a stent change. The protocol is safe as no patients required ancillary procedures to manage an encrusted stent while on surveillance. Patients with a history of pelvic radiation or bowel resection were more likely to require a stent change during their stent surveillance visits.

Lacrimal Gland Microenvironment Changes After Obstruction of Lacrimal Gland Ducts

Purpose

To investigate microenvironment changes of the lacrimal gland after obstruction of lacrimal gland ducts.

Methods

The ducts of rat exorbital lacrimal gland were ligated by sutures for different durations. After that, the sutures in some animals were released, and they were observed for 21 days to evaluate the recovery of the lacrimal gland. Slit lamp and tear secretion test was performed to evaluate ocular surface and lacrimal gland function. The lacrimal gland and cornea were harvested and processed for hematoxylin and eosin staining, oil red O staining, LipidTOX staining, Masson staining, quantitative real time polymerase chain reaction, and immunofluorescence staining.

Results

After the lacrimal gland ducts were blocked, tear secretion and the weight of the lacrimal gland were reduced. Incidence of corneal neovascularization increased after seven days. Intraglandular ducts dilated and acini destroyed. Long-term ligation induced fibrosis and lipid accumulation of the lacrimal glands. Inflammatory cell infiltrated and inflammatory factors upregulated. Proliferative and apoptotic cells increased. Structure of myoepithelial cells and basement membrane was destroyed. The p63 expression increased whereas Pax6 expression decreased. After suture release, tear secretion and structure of acini could recover in less than seven days after ligation, with a decrease in inflammatory cell infiltration and fibrosis relief. Apoptotic cells and proliferative cells increased at five days thereafter. The structure of the myoepithelial cells and basement membrane could not recover three days after ligation, and the number of mesenchymal cells increased in ligation after five to 14 days.

Conclusions

Blockage of the lacrimal gland ducts results in dystrophy of lacrimal gland acini cells, inflammation, and lipid accumulation of the lacrimal gland microenvironment. Long-term duct blockage will cause irreversible lacrimal gland failure.

Comparison of Ureteral Stents on Drainage Performance Under Extrinsic Compression

PURPOSE

By investigating deformation and flow velocity of three commonly used, readily accessible ureteral stents under variant compression and surface change at three time points (new, 1 month or 3 months after implantation), we share our center's experience dealing with ureteral obstruction especially the malignant ones.

MATERIALS AND METHODS

Ureteral double-J (DJ) stents including Cook Universa Soft, Kang Yi Bo (KYB) antireflux and Urovision Visiostar ESWL DJ stents went though scanning microscopic (SEM) analysis. Compression-deformation was measured using digital force gauge. Intraluminal flow velocity was tested with the stents under different compression levels.

RESULT

Urovision Visiostar demonstrated significantly better anti-compression capability. Cook Universa Soft and KYB antireflux showed favorable draining velocity without compression, but the velocity dropped heavily under compression; the velocity of KYB antireflux reduced heavily after 3 months of implantation; Urovision Visiostar achieved the best draining effect under compression at all three time points.

CONCLUSION

The Urovision Visiostar DJ stent demonstrated significantly greater resistance to compression than the other two, and better drainage under compression. Patients with benign or malignant ureteral compression might benefit from using the Urovision Visiostar stents. Large prospective clinical trials are needed for confirmation.

Tumor stent for chronic ureteral obstruction: Which are predictors of stent failure?

PURPOSE

To identify predictors of UROSOFT® tumor stent failure. According to the manufacturer, this reinforced ureteral stent has a maximal dwell time of 6 months. Nonetheless, stent failure may reduce this maximal dwell time.

METHODS

All patients undergoing first-time UROSOFT® tumor stent insertion in our institution between 2010 and 2018 were considered for this retrospective analysis. Primary endpoint was stent failure and defined as premature stent exchange or percutaneous nephrostomy insertion.

RESULTS

182 patients were available for analysis. Median age was 68 years. Causes for tumor stent placement were extrinsic ureteral obstruction in 144 patients (79 %) and intrinsic obstruction in 38 patients (21 %). Tumor stent failure free survival estimates at 1, 2, 3, 4 and 5 months were 89%, 83%, 76%, 65% and 52%, respectively. Patients with stent failure had significantly higher grade of hydronephrosis, higher urinary culture bacterial growth, higher serum WBC, higher CRP and lower eGFR at the time of re-intervention, compared to patients who underwent regular stent exchange. Of all baseline and perioperative parameters, we found bilateral insertion, intrinsic ureteral obstruction, and urinary tract infection (UTI) at time of tumor stent insertion to be significant and independent predictors of stent failure (all p < 0.05).

CONCLUSION

Despite a theoretical maximal dwell time of 6 months, around 50% of all cases are subject to premature stent failure. Predictors of stent failure are bilateral insertion, intrinsic ureteral obstruction, and UTI at the time of tumor stent insertion. Preoperative antibiotic therapy may impact on stent failure rate.

New Stent Technologies

Ureteral stents are an indispensable part of any (endo-) urologic practice. Despite the widely demonstrated advantages of stents, they also carry a considerable risk of side effects and complications, such as urinary symptoms, pain, hematuria, decreased quality of life, stent-related infection, and encrustation. Multiple pathways in preventing or mitigating these side effects and complications and improving stent efficacy have been and are being investigated, including stent architecture and design, biomaterials, and coatings. This article provides an update on currently researched and available stents as well as future perspectives.

Primary ureteral lymphoma presenting as bilateral obstructive uropathy

Primary ureteral lymphomas are rare. We present a case of extranodal B-cell lymphoma of the ureter presenting as asymptomatic bilateral ureteral obstruction. A 34-year-old male was incidentally found to have obstructive uropathy. Imaging showed severe bilateral hydronephrosis and percutaneous nephroureteral stents were placed. Diagnostic work up did not uncover any apparent etiology to the obstruction. Histopathological analysis of the ureter excised during ureteral reimplantation revealed CD20⁺, CD5^-, CD10^- B-cell lymphoma with areas of aggressive disease. The patient received six cycles of R-CHOP chemotherapy and is currently disease free.